Everyone you know has Facebook unless they're weird, but Facebook still has territory left to cover, specifically in the developing world. That plan for global domination includes making Facebook free on mobile.

That's made possible through something called Facebook Zero, a text-only version of the site accessible on a WAP-enabled feature phone, as Quartz reports:

The trick is that Facebook Zero is free, benefiting from what's known as zero rating by the phone companies. Accessing it doesn't rack up any data fees, which are a big deal in emerging markets, where almost everyone is on a prepaid plan.

In the 18 months after Facebook Zero launched in Africa, the number of Africans on Facebook ballooned by 114%. It's hard to directly link that growth to Facebook Zero, but it's easy to see how they could be related. (In the 10 months since then, the number of users of Facebook in Africa grew only 18%.) In Kenya, which is typical for the continent, 99% of access to the internet is accomplished on mobile devices, almost all of which are either feature phones or even more basic models capable only of voice and text messaging. Facebook is now so popular in Africa that the site is driving the adoption of broadband internet, just so users can have faster access to all those pictures and status updates.

And in Mexico, one developing country where carriers don't support Facebook Zero, Facebook is offering something called Facebook for Every Phone, a version installed on SIM cards that works on around 80 percent of phones. These free solutions are crucial—now that Facebook has investors to answer to, growth is more important than ever. The whole article is a worthwhile read—head over to Quartz to check it out. [Quartz]